Interactive
Learner Guide
TM
Cambridge IGCSE / IGCSE (9–1)
Chemistry 0620 / 0971
For examination from 2023
Version 2
© Cambridge University Press & Assessment 2023
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Contents
About this guide
4
Section 1: Syllabus content - what you need to know about
5
Section 2: How you will be assessed
6
Section 3: What skills will be assessed
13
Section 4: Example candidate response
14
Section 5: Revision
18
Section 6: Useful websites
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Learner Guide
About this guide
This guide explains what you need to know about your Cambridge IGCSE Chemistry course and examinations.
It will help you to:
9 understand what skills you should develop by taking this Cambridge IGCSE course
9 understand how you will be assessed
9 understand what we are looking for in the answers you write
9 plan your revision programme
9 revise, by providing revision tips and an interactive revision checklist (Section 5).
The aims of this syllabus are to enable you to:
•
acquire scientific knowledge and understanding of scientific theories and practice
•
develop a range of experimental skills, including handling variables and working safely
•
use scientific data and evidence to solve problems and discuss the limitations of scientific methods
•
communicate effectively and clearly, using scientific terminology, notation and conventions
•
understand that the application of scientific knowledge can benefit people and the environment
•
enjoy science and develop an informed interest in scientific matters which support further study.
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Learner Guide
Section 1: Syllabus content - what you need to know about
This section gives you an outline of the syllabus content for this course. Ask your teacher for more detail about each topic. You
can also find more detail in the Revision checklists of this guide.
1. States of matter
2. Atoms, elements and compounds
3. Stoichiometry
4. Electrochemistry
5. Chemical energetics
6. Chemical reactions
7. Acids, bases and salts
8. The Periodic Table
9. Metals
10. Chemistry of the environment
11. Organic chemistry
12. Experimental techniques and chemical analysis
Make sure you always check the latest syllabus, which is available at www.cambridgeinternational.org
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Learner Guide
Section 2: How you will be assessed
You will be assessed at the end of the course using three components:
•
Paper 1: Multiple Choice (Core) or Paper 2: Multiple Choice (Extended)
•
Paper 3: Theory (Core) or Paper 4: Theory (Extended)
•
Paper 5: Practical Test or Paper 6: Alternative to Practical.
Find out from your teacher which components you will be taking, and when you will be taking them.
Components at a glance
This table summarises the key information about each examination paper. You can find details and advice on how to approach
each component in the ‘About each paper’ sub-section.
Component
Time and
marks
Details
Percentage of
qualification
Paper 1
45 minutes
40 four-choice multiple-choice questions.
30%
Multiple Choice
(Core)
40 marks
Questions will be based on the Core subject content only.
Tests assessment objectives AO1 and AO2.
Externally assessed.
Paper 2
45 minutes
40 four-choice multiple-choice questions.
30%
Multiple Choice
(Extended)
80 marks
Questions will be based on the Core and Supplement subject content.
Tests assessment objectives AO1 and AO2.
Externally assessed.
Paper 3
Theory (Core)
1 hour 15
minutes
80 marks
Short-answer and structured questions.
50%
Questions will be based on the Core subject content only.
Tests assessment objectives AO1 and AO2.
Externally assessed.
Paper 4
Theory
(Extended)
1 hour 15
minutes
80 marks
Short-answer and structured questions.
50%
Questions will be based on the Core and Supplement subject content.
Tests assessment objectives AO1 and AO2.
Externally assessed.
Paper 5
Practical Test
1 hour 15
minutes
Questions will be based on the experimental skills listed in the
syllabus.
40 marks
Tests assessment objective AO3 in a practical context.
20%
Externally assessed.
Paper 6
1 hour
Alternative to
Practical
40 marks
Questions will be based on the experimental skills listed in the
syllabus.
20%
Tests assessment objective AO3 in a written paper.
Externally assessed.
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About each paper
Paper 1: Multiple Choice (Core)
Each of the 40 multiple
choice questions you will
answer has four choices.
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Paper 2: Multiple Choice (Extended)
Each of the 40 multiple
choice questions you will
answer has four choices.
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Paper 3: Theory (Core)
For Paper 3, all questions
are compulsory and there
are no separate sections.
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Paper 4: Theory (Extended)
For Paper 4, all questions
are compulsory and there
are no separate sections.
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Paper 5: Practical Test and Paper 6: Alternative to Practical
Both Paper 5 and Paper 6 include
a planning question. It will be a
6-mark question focusing solely
on the experimental skill of
planning. The planning question
will be identical in both papers.
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Paper 5: Practical Test and Paper 6: Alternative to Practical
Both Paper 5 and Paper 6 include
Notes for use in qualitative
analysis at the end of the paper.
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Section 3: What skills will be assessed
The areas of knowledge, understanding and skills that you will be assessed on are called assessment objectives (AO).
The examiners take account of the following skills areas (assessment objectives) in the examination papers:
•
Knowledge with understanding
•
Handling information and problem solving
•
Experimental skills and investigations
It is important that you know the different weightings (%) of the assessment objectives, as this affects how the examiner will
assess your work. For example, assessment objective 1 (AO1 Knowledge with understanding) is worth 63% of the total marks
in Papers 1, 2, 3 and 4, and AO2 Handling information and problem solving covers the remaining 37%. However, in Paper 5
and Paper 6, only AO3 Experimental skills and investigations is assessed.
Assessment
objectives (AO)
What does the AO
mean?
What do you need to be able to do?
AO1
Remembering facts
and applying these
facts to new situations
You should be able to demonstrate knowledge and understanding of:
Knowledge with
understanding
•
scientific phenomena, facts, laws, definitions, concepts and theories
•
scientific vocabulary, terminology and conventions (including symbols,
quantities and units)
•
scientific instruments and apparatus, including techniques of operation
and aspects of safety
•
scientific and technological applications with their social, economic and
environmental implications.
Subject content defines the factual material that you may be required to
recall and explain.
You will also be asked questions which require you to apply this material to
unfamiliar contexts and to apply knowledge from one area of the syllabus to
another.
AO2
Handling
information and
problem solving
How you extract
information and
rearrange it in a
sensible pattern, and
how you carry out
calculations and make
predictions
You should be able, in words or using other written forms of presentation (i.e.
symbolic, graphical and numerical) to:
•
locate, select, organise and present information from a variety of sources
•
translate information from one form to another
•
manipulate numerical and other data
•
use information to identify patterns, report trends and form conclusions
•
present reasoned explanations for phenomena, patterns and relationships
•
make predictions based on relationships and patterns
•
solve problems, including some of a quantitative nature.
Questions testing these skills may be based on information that is unfamiliar
to you, requiring you to apply the principles and concepts from the syllabus to
a new situation, in a logical, deductive way.
AO3
Planning and carrying
out experiments
Experimental skills
and recording and
and investigations
analysing information
Cambridge IGCSE Chemistry 0620 / 0971
You should be able to:
•
demonstrate knowledge of how to select and safely use techniques,
apparatus and materials (including following a sequence of instructions
where appropriate)
•
plan experiments and investigations
•
make and record observations, measurements and estimates
•
interpret and evaluate experimental observations and data
•
evaluate methods suggest possible improvements.
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Learner Guide
Section 4: Example candidate response
This section takes you through an example question and learner response from a Cambridge IGCSE Chemistry specimen
paper. It will help you to see how to identify command words within questions and to understand what is required in your
response. A command word, is the part of the question that tells you what you need to do with your knowledge. For example,
you might need to describe something, explain something, argue a point of view or list what you know.
All information and advice in this section is specific to the example question and response/
mode answer being demonstrated. It should give you an idea of how your responses might
be viewed by an examiner but it is not a list of what to do in all questions. In your own
examination, you will need to pay careful attention to what each question is asking you to do.
This section is separated as follows:
Question
Command words have been highlighted and their
meaning explained. This will help you to understand
clearly what is required. For more information go to www.
cambridgeinternational.org/exam-administration/what-toexpect-on-exams-day/command-words/
Example candidate response
This is an answer by a real candidate in exam conditions.
Good points and problems have been highlighted.
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Question
Give requires you to produce an
answer from a given source or recall/
memory. Note the instruction that
‘Each letter may be used once,
more than once or not at all’ when
answering this question.
These questions require you to
recall your knowledge of the
electronic configuration of atoms.
The information given in the table and your
knowledge of the electronic configuration
of atoms should enable you to answer this
question fully. Note that even though there
are three marks available, you are required
to fill out four entries in the table.
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Example candidate response
B
The candidate is correct. Atoms in Group III have three electrons in
their outer shell, therefore atom B is the correct choice.
1 mark awarded
A common mistake is candidates often confuse the number of
electrons in the outer shell with the number of electron shells and
therefore select atom D.
B
The candidate is correct. If an atom has 13 protons it must have 13
electrons, therefore atom B is the correct choice.
1 mark awarded
A common mistake is that some candidates are reluctant to select
option B in two consecutive questions. The question states that ‘Each
letter may be used once, more than once, or not at all.’ so you should
select the letter that matches the information.
E
The candidate is correct. Noble gases have a full outer electron shell.
Only atom E has a full outer shell.
1 mark awarded
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C
The candidate is correct. To form a stable negative ion, an atom must
achieve a full outer electron shell by gaining electrons. If an ion is to
have a single negative charge it must gain only one electron. Atom C
has 7 electrons in its outer shell, so when it gains one electron the ion
will have a full outer electron shell and have a 1- charge.
1 mark awarded
A common mistake is that candidates often select atom D because
they know that electrons have a negative charge, and atom D has a
single electron in its outer shell.
18
10
16
8
The candidate is correct. The number of neutrons is calculated by subtracting the proton number from
the mass number. In the sulfur atom that is 34 - 16 = 18 neutrons. The number of protons is given by the
proton number. In the sulfur atom that is 16. Both the number of neutrons and the number of protons in
the sulfur atom were needed for one mark.
The number of electrons in an atom is given by the proton number, but the number of electrons in an
ion has to be calculated using the proton number and the charge on the ion. The oxide ion has a proton
number of 8, but an overall charge of 2-, meaning that there are 8 + 2 = 10 electrons. The number of
protons in an atom or an ion is given by the proton number. So in the oxide ion there are 8 protons.
3 marks awarded
A common mistake is that candidates are often confident working out the numbers of particles in
atoms, but they find ions more challenging. It is important to remember that electrons have a negative
charge, so if an atom gains electrons, the ion will have a negative charge. If an atom loses electrons, the
ion will have a positive charge.
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Learner Guide
Section 5: Revision
This advice will help you revise and prepare for the examinations. It is divided into general advice for all papers and more
specific advice for Paper 1, Paper 2, Paper 3, Paper 4, Paper 5 and Paper 6.
Use the tick boxes
to keep a record of what you have done, what you plan to do or what you understand.
General advice
Before the examination
Find out when the examinations are and plan your revision so you have time to revise. Create a revision timetable and
divide it into sections to cover each topic.
Find out how long each paper is, how many questions you have to answer, how many marks there are for each question,
and work out how long you have for each question.
Know the meaning of the command words used in questions and how to apply them to the information given. Look at
past examination papers and highlight the command words and check what they mean.
Make revision notes. Try different styles of notes.
Work for short periods then have a break. Revise small sections of the syllabus at a time. Test yourself by writing out key
points, redrawing diagrams, etc.
Make sure you define, scientific terms accurately. Definitions must not reuse the words to be defined.
Make your own dictionary or draw up a glossary of key terms for each section of the syllabus. Practise drawing clear,
simple, neat, fully-labelled diagrams
Learn to spell scientific terms correctly.
Have a look at past questions so that you are clear of what to expect in an examination.
Look at mark schemes to help you to understand how the marks are awarded for each question.
In the examination
Read the instructions carefully and answer the right number of questions from the right sections.
Do not answer more questions than are needed, as this will not gain you more marks in the examination.
Plan your time according to the marks for each question. For example, a question worth three marks requires less time
and a shorter answer than one worth 10 marks. If a question has several parts, then the parts with more marks will need
more time and more developed answers.
Do not leave out questions or parts of questions. Remember, no answer means no mark.
Read each question very carefully.
• Identify the command words – you could underline or highlight them.
• Identify the other key words and perhaps underline them too.
• Try to put the question into your own words to understand what it is really asking.
Read all parts of a question before starting your answer. Think carefully about what is needed for each part. You will not
need to repeat material.
Look very carefully at the resource material you are given.
• Read the title, key, axes of graphs, etc. to find out exactly what it is showing you.
• Look for dates, scale, and location.
• Try using coloured pencils or pens to pick out anything that the question asks you about.
Answer the question. This is very important!
Use your knowledge and understanding.
Do not just write all you know, only write what is needed to answer the question.
Plan your answers. Clear, concise, well-ordered, well-argued, well-supported answers get more marks than long,
rambling, muddled, repetitious answers. Quality is better than quantity.
Use scientific terms in your answers as much as possible.
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Use the resource material given in the question to support your answer.
Make sure your writing is clear and easy to read. It is no good writing a brilliant answer if the examiner cannot read it!
Paper 1 and Paper 2 advice
There is 45 minutes for Paper 1 and 2, so you just over one minute to read and answer each question.
Don’t look for patterns in the letter answers you give. If your answers mean you are selecting one letter, e.g. A, more
often than others, it doesn’t matter. Concentrate on answering the question you are doing.
You will likely make fewer mistakes if you write down your working than if you try to work out the answers in your head.
Practise multiple-choice questions and get someone else to mark them. Look for:
• errors
• questions you didn’t read carefully
• topics you don’t know or understand.
Paper 3 and Paper 4 advice
The number of marks for each question or question part often gives you a clue about how many separate points you need
to make in your answer.
The Periodic Table is included in the back of the paper.
Structured questions contain many parts. Often later parts can depend on the answer to earlier parts.
Answer the question being asked. For example, if you are asked to ‘Draw a diagram to show the electron arrangement
in a molecule of hydrogen’, you are asked to draw a ‘molecule’, so two H atoms with a pair of electrons joining them is
needed, not an ‘atom’. If the question asks you to name ‘three other elements’, do not write down the elements which are
given in the question.
Know the chemical terms used in the questions. For example, if a question asks ‘Carboxylic acids can be made by the
oxidation of alcohols. Name a reagent, other than oxygen, which can oxidise alcohols to carboxylic acids’, you need to
understand what the term ‘reagent’ means in order to answer the question correctly.
Know how to write chemical equations in words and using symbols.
Ensure that your answers are specific in your answer and not vague. For example, if a question asks ‘What precautions
must be taken when heating copper(II) sulfate in the laboratory?’, vague answers such as ‘keep away from the reaction’
or ‘don’t breathe in the gas’ will not get the mark. You would need to be specific such as ‘use a fume cupboard’ or ‘carry
out the reaction in a well-ventilated area’.
Do not contradict yourself. For example, if a question asks ‘Give two harmful effects of acid rain’ and you answer ‘Acidifies
lakes and raises the pH’, ‘Acidifies lakes’ is correct, but ‘raises the pH’ has the opposite meaning, that the lakes are more
alkaline.
Keep an eye on the time. Make sure you have time to answer all the questions and return at the end to check your
answers.
Paper 5 advice
Paper 5 assesses experimental skills and investigations. You take the exam in a laboratory under teacher supervision; you
will have your own working space and set of apparatus. It is important that you learn and practise experimental skills
during your course.
This paper will not test specific topic content from the syllabus content. It only tests experimental skills and
investigations (AO3). Any information required to answer the questions in this paper is contained within the paper itself
or should be known from the experimental context, and skills listed in the Revision checklist.
Each question includes the instructions for the experiments you must carry out, space for you to record observations and
data, and space for you to then interpret or process your results. You need to answer all questions.
The number of marks for each question or question part often gives you a clue about how many separate points you need
to make in your answer.
Tests to identify ions and gases (known as Notes for use in qualitative analysis) are included in the exam paper to help you
identify ions and gases.
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Paper 6 advice
Paper 6 assesses experimental skills and investigations. It is a written paper about practical work, so make sure that you
study all the experiments you have done in the classroom and seen demonstrated. You will take this examination under
the same conditions as other written papers. It is important that you learn and practise experimental skills during your
course.
This paper will not test specific topic content from the syllabus content, it tests experimental skills and investigations.
This is AO3. Any information required to answer the questions in this paper is contained within the paper itself or should
be known from the experimental context, and skills listed in the Revision checklist.
The number of marks for each question or question part often gives you a clue about how many separate points you need
to make in your answer.
Tests to identify ions and gases (known as Notes for use in qualitative analysis) are included in the exam paper to help you
identify ions and gases.
Record readings using suitable accuracy, for example:
• volume to the nearest 0.1 cm3
• thermometer readings usually to the nearest 0.5°C
• time to the nearest second.
Record observations in the order the steps are carried out. Observations might include:
• the colour of solids
• the colour of solutions – use colourless if the solution has no colour (‘clear’ is not the same as colourless)
• what you see if you test for a gas, such as bubbles, or fizzing, or effervescence – not just ‘a gas is given off.
Write notes before writing the plan. Clearly state:
• details of apparatus
• quantities of substances to be used
• practical procedures you think should be carried out
• a conclusion.
Make sure any diagrams fill the space given on the paper and are fully labelled.
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Revision checklists
In the next part of this guide we have provided some revision checklists. These include information from the syllabus that you should revise. They don’t contain all the detailed knowledge
you need to know, just an overview. For more detail see the syllabus and talk to your teacher.
The table headings are explained below:
Topic
These are the Core and
Extended topics you need to
know
You should be able to
Content in the syllabus you need to
cover
R
A
G
You can use the tick boxes to show when you have revised
an item and how confident you feel about it.
Comments
You can:
•
add further information of your own, such
as names of case studies needed
•
add learning aids, such as rhymes, poems or
word play
A = AMBER means you are reasonably confident but need
some extra practice
•
pinpoint areas of difficulty you need to
check further with your teacher or textbooks
G = GREEN means you are very confident.
•
include reference to a useful resource
R = RED means you are really unsure and lack confidence;
you might want to focus your revision here and possibly
talk to your teacher for help
As your revision progresses, you can concentrate on the
RED and AMBER items in order to turn them into GREEN
items. You might find it helpful to highlight each topic in
red, orange or green to help you prioritise.
Note: the tables below cannot contain absolutely everything you need to know, but it does use examples wherever it can.
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1 States of matter
You should be able to
Ways to practise skills
R
A
G
Comments
R
A
G
Comments
1.1 Solids, liquids and gases
1
State the distinguishing properties of solids, liquids and gases
2
Describe the structures of solids, liquids and gases in terms of particle
separation, arrangement and motion
3
Describe changes of state in terms of melting, boiling, evaporating, freezing and
condensing
4
Describe the effects of temperature and pressure on the volume of a gas
5
Explain changes of state in terms of kinetic particle theory, including the
interpretation of heating and cooling curves
6
Explain, in terms of kinetic particle theory, the effects of temperature and
pressure on the volume of a gas
1.2 Diffusion
1
Describe and explain diffusion in terms of kinetic particle theory
2
Describe and explain the effect of relative molecular mass on the rate of
diffusion of gases
2 Atoms, elements and compounds
You should be able to
Ways to practise skills
2.1 Elements, compounds and mixtures
1
Describe the differences between elements, molecules, compounds and
mixtures
2.2 Atomic structure and the Periodic Table
1
Describe the structure of the atom as a central nucleus containing neutrons and
protons surrounded by electrons in shells
2
State the relative charges and relative masses of a proton, a neutron and an
electron
3
Define proton number / atomic number as the number of protons in the nucleus
of an atom
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You should be able to
R
Ways to practise skills
4
Define mass number / nucleon number as the total number of protons and
neutrons in the nucleus of an atom
5
Determine the electronic configuration of elements with proton number 1 to 20,
e.g. 2,8,3
6
State that:
a. Group VIII noble gases have a full outer shell
b. the number of outer shell electrons is equal to the group number in Groups I
to VII
c. the number of occupied electron shells is equal to the period number
A
G
Comments
2.3 Isotopes
1
Define isotopes as different atoms of the same element that have the same
number of protons but different numbers of neutrons
2
Interpret and use symbols for atoms, e.g. 12C and ions, e.g.
3
State that isotopes of the same element have the same chemical properties
because they have the same number of electrons and therefore the same
electronic configuration
4
Calculate the relative atomic mass of an element from the relative masses and
abundances of its isotopes
Cl –
35
2.4 Ions and ionic bonds
1
Describe the formation of positive ions, known as cations, and negative ions,
known as anions
2
State that an ionic bond is a strong electrostatic attraction between oppositely
charged ions
3
Describe the formation of ionic bonds between elements from Group I and
Group VII, including the use of dot-and-cross diagrams
4
Describe the properties of ionic compounds:
a. high melting points and boiling points
b. good electrical conductivity when aqueous or molten and poor when solid
5
Describe the giant lattice structure of ionic compounds as a regular arrangement
of alternating positive and negative ions
6
Describe the formation of ionic bonds between ions of metallic and non-metallic
elements, including the use of dot-and-cross diagrams
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Learner Guide
You should be able to
7
Ways to practise skills
R
A
G
Comments
Explain in terms of structure and bonding the properties of ionic compounds:
a. high melting points and boiling points
b. good electrical conductivity when aqueous or molten and poor when solid
2.5 Simple molecules and covalent bonds
1
State that a covalent bond is formed when a pair of electrons is shared between
two atoms leading to noble gas electronic configurations
2
Describe the formation of covalent bonds in simple molecules, including H2,
Cl2, H2O, CH4, NH3 and HCl. Use dot-and-cross diagrams to show the electronic
configurations in these and similar molecules
3
Describe in terms of structure and bonding the properties of simple molecular
compounds:
a. low melting points and boiling points
b. poor electrical conductivity
4
Describe the formation of covalent bonds in simple molecules, including CH3OH,
C2H4, O2, CO2 and N2. Use dot-and-cross diagrams to show the electronic
configurations in these and similar molecules
5
Explain in terms of structure and bonding the properties of simple molecular
compounds:
a. low melting points and boiling points in terms of weak intermolecular forces
(specific types of intermolecular forces are not required)
b. poor electrical conductivity
2.6 Giant covalent structures
1
Describe the giant covalent structures of graphite and diamond
2
Relate the structures and bonding of graphite and diamond to their uses, limited
to:
a. graphite as a lubricant and as an electrode
b. diamond in cutting tools
3
Describe the giant covalent structure of silicon(IV) oxide, SiO2
4
Describe the similarity in properties between diamond and silicon(IV) oxide,
related to their structures
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You should be able to
Ways to practise skills
R
A
G
Comments
R
A
G
Comments
2.7 Metallic bonding
1
Describe metallic bonding as the electrostatic attraction between the positive
ions in a giant metallic lattice and a ‘sea’ of delocalised electrons
2
Explain in terms of structure and bonding the properties of metals:
a. good electrical conductivity
b. malleable and ductile
3 Stoichiometry
You should be able to
Ways to practise skills
3.1 Formulae
1
State the formulae of the elements and compounds named in the subject
content
2
Define the molecular formula of a compound as the number and type of
different atoms in one molecule
3
Deduce the formula of a simple compound from the relative numbers of atoms
present in a model or a diagrammatic representation
4
Construct word equations and symbol equations to show how reactants form
products, including state symbols
5
Define the empirical formula of a compound as the simplest whole number ratio
of the different atoms or ions in a compound
6
Deduce the formula of an ionic compound from the relative numbers of the ions
present in a model or a diagrammatic representation or from the charges on the
ions
7
Construct symbol equations with state symbols, including ionic equations
8
Deduce the symbol equation with state symbols for a chemical reaction, given
relevant information
3.2 Relative masses of atoms and molecules
1
Describe relative atomic mass, Ar, as the average mass of the isotopes of an
element compared to 1/12th of the mass of an atom of 12C
2
Define relative molecular mass, Mr, as the sum of the relative atomic masses.
Relative formula mass, Mr, will be used for ionic compounds.
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Learner Guide
You should be able to
3
Ways to practise skills
R
A
G
Comments
R
A
G
Comments
Calculate reacting masses in simple proportions. Calculations will not involve
the mole concept
3.3 The mole and the Avogadro constant
1
State that concentration can be measured in g / dm3 or mol / dm3
2
State that the mole, mol, is the unit of amount of substance and that one mole
contains 6.02 × 1023 particles, e.g. atoms, ions, molecules; this number is the
Avogadro constant
3
mass (g)
Use the relationship amount of substance
to calculate:
molar mass (g/mol)
a. amount of substance
b. mass
c. molar mass
d. relative atomic mass or relative molecular / formula mass
e. number of particles, using the value of the Avogadro constant
4
Use the molar gas volume, taken as 24 dm3 at room temperature and pressure,
r.t.p. in calculations involving gases
5
Calculate stoichiometric reacting masses, limiting reactants, volumes of gases at
r.t.p., volumes of solutions and concentrations of solutions expressed in g / dm3
and mol / dm3, including conversion between cm3 and dm3
6
Use experimental data from a titration to calculate the moles of solute, or the
concentration or volume of a solution
7
Calculate empirical formulae and molecular formulae, given appropriate data
8
Calculate percentage yield, percentage composition by mass and percentage
purity, given appropriate data
4 Electrochemistry
You should be able to
Ways to practise skills
4.1 Electrolysis
1
26
Define electrolysis as the decomposition of an ionic compound, when molten or
in aqueous solution, by the passage of an electric current
Cambridge IGCSE Chemistry 0620 / 0971
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Ways to practise skills
2
Identify in simple electrolytic cells:
a. the anode as the positive electrode
b. the cathode as the negative electrode
c. the electrolyte as the molten or aqueous substance that undergoes
electrolysis
3
Identify the products formed at the electrodes and describe the observations
made during the electrolysis of:
a. molten lead(II) bromide
b. concentrated aqueous sodium chloride
c. dilute sulfuric acid
using inert electrodes made of platinum or carbon / graphite
4
State that metals or hydrogen are formed at the cathode and that non-metals
(other than hydrogen) are formed at the anode
5
Predict the identity of the products at each electrode for the electrolysis of a
binary compound in the molten state
6
State that metal objects are electroplated to improve their appearance and
resistance to corrosion
7
Describe how metals are electroplated
8
Describe the transfer of charge during electrolysis to include:
a. the movement of electrons in the external circuit
b. the loss or gain of electrons at the electrodes
c. the movement of ions in the electrolyte
9
Identify the products formed at the electrodes and describe the observations
made during the electrolysis of aqueous copper(II) sulfate using inert carbon /
graphite electrodes and when using copper electrodes
10
Predict the identity of the products at each electrode for the electrolysis of a
halide compound in dilute or concentrated aqueous solution
11
Construct ionic half-equations for reactions at the anode (to show oxidation)
and at the cathode (to show reduction)
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4.2 Hydrogen–oxygen fuel cells
1
State that a hydrogen–oxygen fuel cell uses hydrogen and oxygen to produce
electricity with water as the only chemical product
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Describe the advantages and disadvantages of using hydrogen–oxygen fuel cells
in comparison with gasoline / petrol engines in vehicles
5 Chemical energetics
You should be able to
Ways to practise skills
5.1 Exothermic and endothermic reactions
1
State that an exothermic reaction transfers thermal energy to the surroundings
leading to an increase in the temperature of the surroundings
2
State that an endothermic reaction takes in thermal energy from the
surroundings leading to a decrease in the temperature of the surroundings
3
Interpret reaction pathway diagrams showing exothermic and endothermic
reactions
4
State that the transfer of thermal energy during a reaction is called the enthalpy
change, ∆H, of the reaction. ∆H is negative for exothermic reactions and positive
for endothermic reactions
5
Define activation energy, Ea, as the minimum energy that colliding particles must
have to react
6
Draw and label reaction pathway diagrams for exothermic and endothermic
reactions using information provided, to include:
a. reactants
b. products
c. enthalpy change of the reaction, ∆H
d. activation energy, Ea
7
State that bond breaking is an endothermic process and bond making is an
exothermic process and explain the enthalpy change of a reaction in terms of
bond breaking and bond making
8
Calculate the enthalpy change of a reaction using bond energies
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6 Chemical reactions
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6.1 Physical and chemical changes
1
Identify physical and chemical changes, and understand the differences between
them
6.2 Rate of reaction
Describe the effect on the rate of reaction of:
a. changing the concentration of solutions
b. changing the pressure of gases
c. changing the surface area of solids
d. changing the temperature
e. adding or removing a catalyst, including enzymes
2
State that a catalyst increases the rate of a reaction and is unchanged at the end
of a reaction
3
Describe practical methods for investigating the rate of a reaction including
change in mass of a reactant or a product and the formation of a gas
4
Interpret data, including graphs, from rate of reaction experiments
5
Describe collision theory in terms of:
a. number of particles per unit volume
b. frequency of collisions between particles
c. kinetic energy of particles
d. activation energy, Ea
6
Describe and explain the effect on the rate of reaction of:
a. changing the concentration of solutions
b. changing the pressure of gases
c. changing the surface area of solids
d. changing the temperature
e. adding or removing a catalyst, including enzymes
using collision theory
7
State that a catalyst decreases the activation energy, Ea, of a reaction
8
Evaluate practical methods for investigating the rate of a reaction including
change in mass of a reactant or a product and the formation of a gas
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6.3 Reversible reactions and equilibrium
1
2
State that some chemical reactions are reversible as shown by the symbol ⇌
Describe how changing the conditions can change the direction of a reversible
reaction for:
a. the effect of heat on hydrated compounds
b. the addition of water to anhydrous compounds including copper(II) sulfate
and cobalt(II) chloride
3
State that a reversible reaction in a closed system is at equilibrium when:
a. the rate of the forward reaction is equal to the rate of the reverse reaction
b. the concentrations of reactants and products are no longer changing
4
Predict and explain, for any reversible reaction, how the position of equilibrium
is affected by:
a. changing temperature
b. changing pressure
c. changing concentration
d. using a catalyst
using information provided
5
State the symbol equation for the production of ammonia in the Haber process,
6
N2(g) + 3H2(g) ⇌ 2NH3(g)
State the sources of the hydrogen (methane) and nitrogen (air) in the Haber
process
7
State the typical conditions in the Haber process as 450 °C, 20 000 kPa / 200
atm and an iron catalyst
8
State the symbol equation for the conversion of sulfur dioxide to sulfur trioxide
in the Contact process, 2SO2(g) + O2(g) ⇌ 2SO3(g)
9
State the sources of the sulfur dioxide (burning sulfur or roasting sulfide ores)
and oxygen (air) in the Contact process
10
State the typical conditions for the conversion of sulfur dioxide to sulfur trioxide
in the Contact process as 450 °C, 200 kPa / 2 atm and a vanadium(V) oxide
catalyst
11
Explain, in terms of rate of reaction and position of equilibrium, why the typical
conditions stated are used in the Haber process and in the Contact process,
including safety considerations and economics
30
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6.4 Redox
1
Use a Roman numeral to indicate the oxidation number of an element in a
compound
2
Define redox reactions as involving simultaneous oxidation and reduction
3
Define oxidation as gain of oxygen and reduction as loss of oxygen
4
Identify redox reactions as reactions involving gain and loss of oxygen
5
Identify oxidation and reduction in redox reactions
6
Define oxidation in terms of:
a. loss of electrons
b. an increase in oxidation number
7
Define reduction in terms of:
a. gain of electrons
b. a decrease in oxidation number
8
Identify redox reactions as reactions involving gain and loss of electrons
9
Identify redox reactions by changes in oxidation number using:
a. the oxidation number of elements in their uncombined state is zero
b. the oxidation number of a monatomic ion is the same as the charge on the
ion
c. the sum of the oxidation numbers in a compound is zero
d. the sum of the oxidation numbers in an ion is equal to the charge on the ion
10
Identify redox reactions by the colour changes involved when using acidified
aqueous potassium manganate(VII) or aqueous potassium iodide
11
Define an oxidising agent as a substance that oxidises another substance and is
itself reduced
12
Define a reducing agent as a substance that reduces another substance and is
itself oxidised
13
Identify oxidising agents and reducing agents in redox reactions
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7 Acids, bases and salts
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7.1 The characteristic properties of acids and bases
1
Describe the characteristic properties of acids in terms of their reactions with:
a. metals
b. bases
c. carbonates
2
Describe acids in terms of their effect on:
a. litmus
b. thymolphthalein
c. methyl orange
3
State that bases are oxides or hydroxides of metals and that alkalis are soluble
bases
4
Describe the characteristic properties of bases in terms of their reactions with:
a. acids
b. ammonium salts
5
Describe alkalis in terms of their effect on:
a. litmus
b. thymolphthalein
c. methyl orange
6
State that aqueous solutions of acids contain H+ ions and aqueous solutions of
alkalis contain OH– ions
7
Describe how to compare hydrogen ion concentration, neutrality, relative acidity
and relative alkalinity in terms of colour and pH using universal indicator paper
8
Describe the neutralisation reaction between an acid and an alkali to produce
water, H+ (aq) + OH– (aq) → H2O (l)
9
Define acids as proton donors and bases as proton acceptors
10
Define a strong acid as an acid that is completely dissociated in aqueous
solution and a weak acid as an acid that is partially dissociated in aqueous
solution
11
State that hydrochloric acid is a strong acid, as shown by the symbol equation,
HCl (aq) → H+(aq) + Cl –(aq)
12
State that ethanoic acid is a weak acid, as shown by the symbol equation,
–
CH3COOH(aq) ⇌ H+ (aq) + CH3COO (aq)
32
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7.2 Oxides
1
Classify oxides as acidic, including SO2 and CO2, or basic, including CuO and
CaO, related to metallic and non-metallic character
2
Describe amphoteric oxides as oxides that react with acids and with bases to
produce a salt and water
3
Classify Al 2O3 and ZnO as amphoteric oxides
7.3 Preparation of salts
1
Describe the preparation, separation and purification of soluble salts by reaction
of an acid with:
a. an alkali by titration
b. excess metal
c. excess insoluble base
d. excess insoluble carbonate
2
Describe the general solubility rules for salts:
a. sodium, potassium and ammonium salts are soluble
b. nitrates are soluble
c. chlorides are soluble, except lead and silver
d. sulfates are soluble, except barium, calcium and lead
e. carbonates are insoluble, except sodium, potassium and ammonium
f. hydroxides are insoluble, except sodium, potassium, ammonium and calcium
(partially)
3
Define a hydrated substance as a substance that is chemically combined with
water and an anhydrous substance as a substance containing no water
4
Define the term water of crystallisation as the water molecules present in
crystals, e.g. CuSO4•5H2O and CoCl2•6H2O
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8 The Periodic Table
2You should be able to
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8.1 Arrangement of elements
1
Describe the Periodic Table as an arrangement of elements in periods and groups
and in order of increasing proton / atomic number
2
Describe the change from metallic to non-metallic character across a period
3
Describe the relationship between group number and the charge of the ions
formed from elements in that group
4
Explain similarities in the chemical properties of elements in the same group of
the Periodic Table in terms of their electronic configuration
5
Explain how the position of an element in the Periodic Table can be used to
predict its properties
6
Identify trends in groups, given information about the elements
8.2 Group I properties
1
Describe the Group I alkali metals, lithium, sodium and potassium, as relatively
soft metals with general trends down the group, limited to:
a. decreasing melting point
b. increasing density
c. increasing reactivity
2
Predict the properties of other elements in Group I, given information about the
elements
8.3 Group VII properties
1
Describe the Group VII halogens, chlorine, bromine and iodine, as diatomic nonmetals with general trends down the group, limited to:
a. increasing density
b. decreasing reactivity
2
State the appearance of the halogens at r.t.p. as:
a. chlorine, a pale yellow-green gas
b. bromine, a red-brown liquid
c. iodine, a grey-black solid
3
Describe and explain the displacement reactions of halogens with other halide
ions
34
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Predict the properties of other elements in Group VII, given information about
the elements
8.4 Transition elements
1
Describe the transition elements as metals that:
a. have high densities
b. have high melting points
c. form coloured compounds
d. often act as catalysts as elements and in compounds
2
Describe transition elements as having ions with variable oxidation numbers,
including iron(II) and iron(III)
8.5 Noble gases
1
Describe the Group VIII noble gases as unreactive, monatomic gases and explain
this in terms of electronic configuration
9 Metals
You should be able to
Ways to practise skills
9.1 Properties of metals
1
Compare the general physical properties of metals and non-metals, including:
a. thermal conductivity
b. electrical conductivity
c. malleability and ductility
d. melting points and boiling points
2
Describe the general chemical properties of metals, limited to their reactions
with:
a. dilute acids
b. cold water and steam
c. oxygen
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9.2 Uses of metals
1
Describe the uses of metals in terms of their physical properties, including:
a. aluminium in the manufacture of aircraft because of its low density
b. aluminium in the manufacture of overhead electrical cables because of its
low density and good electrical conductivity
c. aluminium in food containers because of its resistance to corrosion
d. copper in electrical wiring because of its good electrical conductivity and
ductility
9.3 Alloys and their properties
1
Describe an alloy as a mixture of a metal with other elements, including:
e. brass as a mixture of copper and zinc
f. stainless steel as a mixture of iron and other elements such as chromium,
nickel and carbon
2
State that alloys can be harder and stronger than the pure metals and are more
useful
3
Describe the uses of alloys in terms of their physical properties, including
stainless steel in cutlery because of its hardness and resistance to rusting
4
Identify representations of alloys from diagrams of structure
5
Explain in terms of structure how alloys can be harder and stronger than the
pure metals because the different sized atoms in alloys mean the layers can no
longer slide over each other
9.4 Reactivity series
1
State the order of the reactivity series as: potassium, sodium, calcium,
magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold
2
Describe the reactions, if any, of:
g. potassium, sodium and calcium with cold water
h. magnesium with steam
i. magnesium, zinc, iron, copper, silver and gold with dilute hydrochloric acid
and explain these reactions in terms of the position of the metals in the
reactivity series
3
Deduce an order of reactivity from a given set of experimental results
36
Cambridge IGCSE Chemistry 0620 / 0971
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4
Describe the relative reactivities of metals in terms of their tendency to form
positive ions, by displacement reactions, if any, with the aqueous ions of
magnesium, zinc, iron, copper and silver
5
Explain the apparent unreactivity of aluminium in terms of its oxide layer
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9.5 Corrosion of metals
1
State the conditions required for the rusting of iron and steel to form hydrated
iron(III) oxide
2
State some common barrier methods, including painting, greasing and coating
with plastic
3
Describe how barrier methods prevent rusting by excluding oxygen or water
4
Describe the use of zinc in galvanising as an example of a barrier method and
sacrificial protection
5
Explain sacrificial protection in terms of the reactivity series and in terms of
electron loss
9.6 Extraction of metals
1
Describe the ease in obtaining metals from their ores, related to the position of
the metal in the reactivity series
2
Describe the extraction of iron from hematite in the blast furnace, limited to:
a. the burning of carbon (coke) to provide heat and produce carbon dioxide
b. the reduction of carbon dioxide to carbon monoxide
c. the reduction of iron(III) oxide by carbon monoxide
d. the thermal decomposition of calcium carbonate / limestone to produce
calcium oxide
e. the formation of slag
Symbol equations are not required
3
State that the main ore of aluminium is bauxite and that aluminium is extracted
by electrolysis
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4
State the symbol equations for the extraction of iron from hematite
a. C + O2 → CO2
b. C + CO2 → 2CO
c. Fe2O3 + 3CO → 2Fe + 3CO2
d. CaCO3 → CaO + CO2
e. CaO + SiO2 → CaSiO3
5
Describe the extraction of aluminium from purified bauxite / aluminium oxide,
including:
a. the role of cryolite
b. why the carbon anodes need to be regularly replaced
c. the reactions at the electrodes, including ionic half-equations
Details of the purification of bauxite are not required
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10 Chemistry of the environment
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10.1 Water
1
Describe chemical tests for the presence of water using anhydrous cobalt(II)
chloride and anhydrous copper(II) sulfate
2
Describe how to test for the purity of water using melting point and boiling
point
3
Explain that distilled water is used in practical chemistry rather than tap water
because it contains fewer chemical impurities
4
State that water from natural sources contains a variety of substances, including:
a. dissolved oxygen
b. metal compounds
c. plastics
d. sewage
e. harmful microbes
f. nitrates from fertilisers
g. phosphates from fertilisers and detergents
5
State that some of these substances are beneficial, including:
a. dissolved oxygen for aquatic life
b. some metal compounds provide essential minerals for life
38
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State that some of these substances are potentially harmful, including:
a. some metal compounds are toxic
b. some plastics harm aquatic life
c. sewage contains harmful microbes which cause disease
d. nitrates and phosphates lead to deoxygenation of water and damage to
aquatic life
Details of the eutrophication process are not required.
Describe the purification of the domestic water supply in terms of:
a. sedimentation and filtration to remove solids
b. use of carbon to remove tastes and odours
c. chlorination to kill microbes
10.2 Fertilisers
1
State that ammonium salts and nitrates are used as fertilisers
2
Describe the use of NPK fertilisers to provide the elements nitrogen, phosphorus
and potassium for improved plant growth
10.3 Air quality and climate
1
State the composition of clean, dry air as approximately 78% nitrogen, N2, 21%
oxygen, O2 and the remainder as a mixture of noble gases and carbon dioxide,
CO2
2
State the source of each of these air pollutants, limited to:
a. carbon dioxide from the complete combustion of carbon-containing fuels
b. carbon monoxide and particulates from the incomplete combustion of
carbon-containing fuels
c. methane from the decomposition of vegetation and waste gases from
digestion in animals
d. oxides of nitrogen from car engines
e. sulfur dioxide from the combustion of fossil fuels which contain sulfur
compounds
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3
State the adverse effects of these air pollutants, limited to:
a. carbon dioxide: higher levels of carbon dioxide leading to increased global
warming, which leads to climate change
b. carbon monoxide: toxic gas
c. particulates: increased risk of respiratory problems and cancer
d. methane: higher levels of methane leading to increased global warming,
which leads to climate change
e. oxides of nitrogen: acid rain, photochemical smog and respiratory problems
f. sulfur dioxide: acid rain
4
State and explain strategies to reduce the effects of these environmental issues,
limited to:
a. climate change: planting trees, reduction in livestock farming, decreasing use
of fossil fuels, increasing use of hydrogen and renewable energy, e.g. wind,
solar
b. acid rain: use of catalytic converters in vehicles, reducing emissions of sulfur
dioxide by using low-sulfur fuels and flue gas desulfurisation with calcium
oxide
5
Describe photosynthesis as the reaction between carbon dioxide and water to
produce glucose and oxygen in the presence of chlorophyll and using energy
from light
6
State the word equation and symbol equation for photosynthesis,
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carbon dioxide + water → glucose + oxygen
7
Describe how the greenhouse gases carbon dioxide and methane cause global
warming, limited to:
a. the absorption, reflection and emission of thermal energy
b. reducing thermal energy loss to space
8
Explain how oxides of nitrogen form in car engines and describe their removal by
catalytic converters, e.g. 2CO + 2NO → 2CO2 + N2
9
State the symbol equation for photosynthesis,
6CO2 + 6H2O → C6H12O6 + 6O2
40
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11 Organic chemistry
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11.1 Formulae, functional groups and terminology
1
Draw and interpret the displayed formula of a molecule to show all the atoms
and all the bonds
2
Write and interpret general formulae of compounds in the same homologous
series, limited to:
a. alkanes, CnH2n+2
b. alkenes, CnH2n
c. alcohols, CnH2n+1OH
d. carboxylic acids, CnH2n+1COOH
3
Identify a functional group as an atom or group of atoms that determine the
chemical properties of a homologous series
4
State that a homologous series is a family of similar compounds with similar
chemical properties due to the presence of the same functional group
5
State that a saturated compound has molecules in which all carbon–carbon
bonds are single bonds
6
State that an unsaturated compound has molecules in which one or more
carbon–carbon bonds are not single bonds
7
State that a structural formula is an unambiguous description of the way the
atoms in a molecule are arranged, including CH2=CH2, CH3CH2OH, CH3COOCH3
8
Define structural isomers as compounds with the same molecular formula,
but different structural formulae, including C4H10 as CH3CH2CH2CH3 and
CH3CH(CH3)CH3 and C4H8 as CH3CH2CH=CH2 and CH3CH=CHCH3
9
Describe the general characteristics of a homologous series as:
a. having the same functional group
b. having the same general formula
c. differing from one member to the next by a –CH2– unit
d. displaying a trend in physical properties
e. sharing similar chemical properties
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11.2 Naming organic compounds
1
Name and draw the displayed formulae of:
a. methane and ethane
b. ethene
c. ethanol
d. ethanoic acid
e. the products of the reactions stated in sections 11.4–11.7
2
State the type of compound present, given a chemical name ending in -ane,
-ene, -ol, or -oic acid or from a molecular formula or displayed formula
3
Name and draw the structural and displayed formulae of unbranched:
a. alkanes
b. alkenes, including but-1-ene and but-2-ene
c. alcohols, including propan-1-ol, propan-2-ol, butan-1-ol and butan-2-ol
d. carboxylic acids
containing up to four carbon atoms per molecule
4
Name and draw the displayed formulae of the unbranched esters which can be
made from unbranched alcohols and carboxylic acids, each containing up to four
carbon atoms
11.3 Fuels
1
Name the fossil fuels: coal, natural gas and petroleum
2
Name methane as the main constituent of natural gas
3
State that hydrocarbons are compounds that contain hydrogen and carbon only
4
State that petroleum is a mixture of hydrocarbons
5
Describe the separation of petroleum into useful fractions by fractional
distillation
6
Describe how the properties of fractions obtained from petroleum change from
the bottom to the top of the fractionating column, limited to:
e. decreasing chain length
f. higher volatility
g. lower boiling points
h. lower viscosity
42
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Name the uses of the fractions as:
a. refinery gas fraction for gas used in heating and cooking
b. gasoline / petrol fraction for fuel used in cars
c. naphtha fraction as a chemical feedstock
d. kerosene / paraffin fraction for jet fuel
e. diesel oil / gas oil fraction for fuel used in diesel engines
f. fuel oil fraction for fuel used in ships and home heating systems
g. lubricating oil fraction for lubricants, waxes and polishes
h. bitumen fraction for making roads
11.4 Alkanes
1
State that the bonding in alkanes is single covalent and that alkanes are
saturated hydrocarbons
2
Describe the properties of alkanes as being generally unreactive, except in terms
of combustion and substitution by chlorine
3
State that in a substitution reaction one atom or group of atoms is replaced by
another atom or group of atoms
4
Describe the substitution reaction of alkanes with chlorine as a photochemical
reaction, with ultraviolet light providing the activation energy, Ea, and draw the
structural or displayed formulae of the products, limited to monosubstitution
11.5 Alkenes
1
State that the bonding in alkenes includes a double carbon–carbon covalent
bond and that alkenes are unsaturated hydrocarbons
2
Describe the manufacture of alkenes and hydrogen by the cracking of larger
alkane molecules using a high temperature and a catalyst
3
Describe the reasons for the cracking of larger alkane molecules
4
Describe the test to distinguish between saturated and unsaturated
hydrocarbons by their reaction with aqueous bromine
5
State that in an addition reaction only one product is formed
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Describe the properties of alkenes in terms of addition reactions with:
a. bromine or aqueous bromine
b. hydrogen in the presence of a nickel catalyst
c. steam in the presence of an acid catalyst
and draw the structural or displayed formulae of the products
11.6 Alcohols
1
Describe the manufacture of ethanol by:
a. fermentation of aqueous glucose at 25–35 °C in the presence of yeast and in
the absence of oxygen
b. catalytic addition of steam to ethene at 300 °C and 6000 kPa / 60 atm in
the presence of an acid catalyst
2
Describe the combustion of ethanol
3
State the uses of ethanol as:
a. a solvent
b. a fuel
4
Describe the advantages and disadvantages of the manufacture of ethanol by:
a. fermentation
b. catalytic addition of steam to ethene
11.7 Carboxylic acids
1
Describe the reactions of carboxylic acids with:
a. metals
b. bases
c. carbonates
including names and formulae of the salts produced
2
Describe the formation of ethanoic acid by the oxidation of ethanol:
a. with acidified aqueous potassium manganate(VII)
b. by bacterial oxidation during vinegar production
3
Describe the reaction of a carboxylic acid with an alcohol using an acid catalyst
to form an ester
11.8 Polymers
1
44
Define polymers as large molecules built up from many smaller molecules called
monomers
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2
Describe the formation of poly(ethene) as an example of addition
polymerisation using ethene monomers
3
State that plastics are made from polymers
4
Describe how the properties of plastics have implications for their disposal
5
Describe the environmental challenges caused by plastics, limited to:
a. disposal in land fill sites
b. accumulation in oceans
c. formation of toxic gases from burning
6
Identify the repeat units and / or linkages in addition polymers and in
condensation polymers
7
Deduce the structure or repeat unit of an addition polymer from a given alkene
and vice versa
8
Deduce the structure or repeat unit of a condensation polymer from given
monomers and vice versa, limited to:
a. polyamides from a dicarboxylic acid and a diamine
b. polyesters from a dicarboxylic acid and a diol
9
Describe the differences between addition and condensation polymerisation
10
Describe and draw the structure of
a. nylon, a polyamide
b. PET, a polyester
O
O
C
C
O
O
C
C
O
N
N
H
H
O
O
O
C
C
O
O
C
C
A
G
Comments
O
N
N
H
H
O
C
O
The full name for PET, polyethylene terephthalate, is not required.
11
State that PET can be converted back into monomers and re-polymerised
12
Describe proteins as natural polyamides and are formed from amino acid
monomers with the general structure
H
H
Cambridge IGCSE Chemistry 0620 / 0971
O
R
N
C
H
C
O
H
, where R represents different types of side chain
45
Learner Guide
You should be able to
13
Ways to practise skills
Describe and draw the structure of proteins as:
H
O
N
C
N
C
H
O
H
O
N
C
R
A
G
Comments
R
A
G
Comments
12 Experimental techniques and chemical analysis
Topic
You should be able to
12.1 Experimental design
1
Name appropriate apparatus for the measurement of time, temperature, mass
and volume, including:
a. stop-watches
b. thermometers
c. balances
d. burettes
e. volumetric pipettes
f. measuring cylinders
g. gas syringes
2
Suggest advantages and disadvantages of experimental methods and apparatus
3
Describe a:
a. solvent as a substance that dissolves a solute
b. solute as a substance that is dissolved in a solvent
c. solution as a liquid mixture composed of two or more substances
d. saturated solution as a solution containing the maximum concentration of a
solute dissolved in the solvent
e. residue as a substance that remains after evaporation, distillation, filtration
or any similar process
f. filtrate as a liquid or solution that has passed through a filter
12.2 Acid–base titrations
1
46
Describe an acid–base titration to include the use of a:
a. burette
b. volumetric pipette
c. suitable indicator
Cambridge IGCSE Chemistry 0620 / 0971
Learner Guide
Topic
2
You should be able to
R
A
G
Comments
Describe how to identify the end-point of a titration using an indicator
12.3 Chromatography
1
Describe how paper chromatography is used to separate mixtures of soluble
substances, using a suitable solvent
2
Interpret simple chromatograms to identify:
a. unknown substances by comparison with known substances
b. pure and impure substances
4
State and use the equation for the retention factor, Rf:
Rf = distance travelled by substance
distance travelled by solvent
12.4 Separation and purification
1
Describe and explain methods of separation and purification using:
a. a suitable solvent
b. filtration
c. crystallisation
d. simple distillation
e. fractional distillation
2
Suggest suitable separation and purification techniques, given information
about the substances involved
3
Identify substances and assess their purity using melting point and boiling point
information
12.5 Identification of ions and gases
1
Describe tests to identify the anions:
a. carbonate, CO32–, by reaction with dilute acid and then testing for carbon
dioxide gas
b. chloride, Cl–, bromide, Br–, and iodide, I–, by acidifying with dilute nitric acid
then adding aqueous silver nitrate
c. nitrate, NO3–, by reduction with aluminium and aqueous sodium hydroxide
and then testing for ammonia gas
d. sulfate, SO42–, by acidifying with dilute nitric acid then adding aqueous
barium
e. nitrate
f. sulfite, SO32–, by reaction with acidified aqueous potassium manganate(VII)
Cambridge IGCSE Chemistry 0620 / 0971
47
Learner Guide
Topic
You should be able to
2
Describe tests using aqueous sodium hydroxide and aqueous ammonia to
identify the aqueous cations:
a. aluminium, Al3+
b. ammonium, NH4+
c. calcium, Ca2+
d. chromium(III), Cr3+
e. copper(II), Cu2+
f. iron(II), Fe2+
g. iron(III), Fe3+
h. zinc, Zn2+
3
Describe tests to identify the gases:
a. ammonia, NH3, using damp red litmus paper
b. carbon dioxide, CO2, using limewater
c. chlorine, Cl2, using damp litmus paper
d. hydrogen, H2, using a lighted splint
e. oxygen, O2, using a glowing splint
f. sulfur dioxide, SO2, using acidified aqueous potassium manganate(VII)
4
Describe the use of a flame test to identify the cations:
a. lithium, Li+
b. sodium, Na+
c. potassium, K+
d. calcium, Ca2+
e. barium, Ba2+
f. copper(II), Cu2+
48
R
A
G
Comments
Cambridge IGCSE Chemistry 0620 / 0971
Learner Guide
Section 6: Useful websites
The resources listed below will help you to revise and study for your Cambridge IGCSE Chemistry course.
These resources have not been through the Cambridge quality assurance process but have been found suitable for use with
various parts of the syllabus. This list includes website links providing direct access to internet resources. Cambridge is not
responsible for the accuracy or content of information contained in these resources. The inclusion of a link to an external
website should not be understood to be an endorsement of that website or the site's owners (or their products/services).
https://www.chemguide.co.uk
A general chemistry resources website.
https://phet.colorado.edu/
Interactive simulations for science and maths subjects.
https://www.rsc.org/
The Royal Society of Chemistry website is full of different resources and information including an interactive periodic table
and much more.
https://www.bbc.co.uk/bitesize/subjects/zs6hvcw
Online study material for chemistry from the BBC.
You can find a resource list, including endorsed resources to support Cambridge O Level Chemistry on our public website
[here]
Endorsed resources have been written to be closely aligned to the syllabus they support, and have been through a detailed
quality assurance process. All textbooks endorsed by Cambridge International for this syllabus are the ideal resource to be
used alongside this Learner Guide.
In addition to reading the syllabus, you should refer to the past and specimen papers.
Cambridge IGCSE Chemistry 0620 / 0971
49
Cambridge Assessment International Education
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t: +44 1223 553554
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